1814.] On the Hypotheses of Galvanism. 39 



electrical conditions of the particles of which it is composed, each 

 particle being attracted to that end of the pile which possesses an 

 electricity opposite to itself: lie also supposes that the chemical 

 effects are a necessary, although a secondary, step in the operation. 

 So far it will probably be fuund superior to the other mcdi^'cations 

 of the electrical hypothesis; but it will, like them, be defective, 

 as affording no adequate explanation of the progressive increase of 

 power in the apparatus ; for whether we conceive the equalizing 

 effect of the lluid to depend simply upon its conducting property, 

 or upon the electrical state of its constituent particles, there ap- 

 pears no reason why a perfect equilibrium should not be established 

 between each pair of metals, so as to reduce the action of the 

 whole pile to the sole difference between the first copper and the 

 last zinc plate. It also labours under the objection, which has been 

 already pointed out, that it affords no source for the large supply of 

 electricity which is constantly evolved ; like the other hypotheses, 

 it supposes merely a new distribution of the electric fluid through 

 the parts of the apparatus contiguous to each other.* 



From these remarks it will appear, that the hypothesis which has 

 been formed to account for the action of the Galvanic pile upon 

 electrical principles is inadequate to the purpose, and must be 

 abandoned. And besides these general views, there are particular 

 facts that seem quite irreconcilable to it, some of which I shall now 

 detail. 1. The experiments which show that the pile has its action 

 suspended in vacuo, or in any gas which does not contain oxygen, 

 is decidedly adverse to the electrical hypothesis ; the fact has, 

 indeed, been denied by Volta ; t but the weight of authority on 

 the contrary side is too powerful to admit of any doubt. % The 

 experiment of ^ir H Davy may be considered as an extension of 

 this principle, that although In ordinary circumstances a pile cannot 

 act in vacuo, yet that its action may be established by the addition 

 of an acid to the fluid which is interposed between the phites, I 

 am not aware of any method by which these experiments can he 

 reconciled to the electrical hypothesis. 2. It has always been an 



• Although this seems to lie the fair deduction from Sir IT. Davy's principles, 

 yet he ha>, on one occasion, given an ex|>lanation of the action of the pile, which 

 is coniiderably difl'erent. Supposing the elements to consist of copper, zinc, and 

 fluid, the copper and zinc, by their action upon each other, become respectively 

 negative and positive. Betueen the zinc and the second copper plate (lie fluid 

 intervenes ; and he sJiys, " with regard to electricities of such very low intensity, 

 water is an in^ulatinp body ;"' (a) therefore no action can lajie place between tlie 

 first zinc and the second coppi-r plate across tlie fluid. According to this, which 

 must he regnrdcd as quite a new liypolhesis, and one directly the reverse of that 

 adopted by Volta, the metals of e.icli pair of plates are indiridually plus and 

 minus; but each pair can have no action upon the neighbouring pairs ; and the 

 ivorsc conductor the fluid is which is employed, the more cumplele will be the 

 aetiuu of the instrument. 



t Ann, de Chim, xlii. 281. % Haldanc, Pepys, Biot, A'an Marum^ 4c. 



{a) Phil. Trans. 1807, S 9. 



